二相流噴嘴效率實驗與分析

Abstract

本研究為二相流噴嘴的全流式發電實驗，於研究中完成建設全流式超音速二相流噴嘴測試及發電平台，且建設鍋爐系統來模擬地熱庫之溫度及壓力，透過收集不同溫度之下的全流式發電實驗數據來分析最佳效率之噴嘴。 本研究中所使用的渦輪機為斜衝式渦輪機，其優點為不易堆積雜質對於發電平台的維護及保養有一定的幫助，而使用的二相流噴嘴為漸縮漸擴噴嘴，其優點在於能在二相流達到音速時持續將流體加速成為超音速流體，以利實驗中能獲得較大的質量流率，而在本次實驗中觀察到隨著使用較大喉部直徑之噴嘴能獲得較大的質量流率，在獲得較大質量流率的條件下能獲得較大的發電量，但對於渦輪機機本身的動能轉換率卻並非是最大質量流率之噴嘴擁有最佳之動能轉換率，且在計算斜衝式渦輪機的理論發電量下也有相同的情形產生，因此推斷轉換效率可能會與噴嘴的噴射流體型態有關。

This research focuses on the development and experimentation of a two-phase flow nozzle for a total flow geothermal power generation system. The study involves the construction of a test and power generation platform for a total-flow supersonic two-phase flow nozzle. Additionally, a boiler system is established to simulate the temperature and pressure conditions of a geothermal reservoir. The experimental data collected at various temperatures will be analyzed to determine the optimal efficiency of the nozzle. The turbine used in this study is a turgo turbine, chosen for its resistance to impurity accumulation, contributing to easier maintenance and upkeep of the power generation platform. The two-phase flow nozzle employed is a converging-diverging nozzle, selected for its ability to continuously accelerate the fluid to supersonic speeds as the two-phase flow reaches sonic velocity. This facilitates obtaining a larger mass flow rate during the experiment. Observations from the experiment indicate that nozzles with larger throat diameters result in increased mass flow rates, leading to higher power generation. However, it is noted that the nozzle with the maximum mass flow rate does not necessarily possess the optimal kinetic energy conversion rate for the turbine. This observation is consistent with the theoretical power generation calculations for the inclined impeller turbine. Consequently, it is inferred that the conversion efficiency may be related to the jet fluid pattern of the nozzle.